Example of a three-dimensional silicate is:

Options

A. Zeolites
B. Ultramarines
C. Feldspars
D. Beryls

Explanation

To determine the example of a three-dimensional silicate from the given options (zeolites, ultramarines, feldspars, or beryls), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Silicates**: Silicates are minerals that contain silicon and oxygen. They can form various structures based on how the silicon-oxygen tetrahedra (SiO4) are arranged.

2. **Types of Silicate Structures**: Silicates can be classified into different categories based on their structure:
- **Nesosilicates**: Independent tetrahedra
- **Sorosilicates**: Double tetrahedra
- **Cyclic Silicates**: Tetrahedra arranged in rings
- **Chain Silicates**: Tetrahedra linked in chains
- **Sheet Silicates**: Tetrahedra arranged in sheets
- **Three-Dimensional Silicates (Tectosilicates)**: Tetrahedra linked in a three-dimensional framework.

3. **Identifying 3D Silicates**: In three-dimensional silicates, each tetrahedron shares its oxygen atoms with adjacent tetrahedra, creating a robust three-dimensional network.

4. **Analyzing the Options**:
- **Zeolites**: These are 3D silicates known for their porous structure and ability to exchange cations.
- **Ultramarines**: These are also 3D silicates, typically used as pigments.
- **Feldspars**: This group includes minerals that are 3D silicates and are very common in the Earth's crust.
- **Beryls**: Beryls are not classified as silicates; they are cyclosilicates.

5. **Conclusion**: Since zeolites, ultramarines, and feldspars are all examples of three-dimensional silicates, the correct answer to the question is that all three (zeolites, ultramarines, and feldspars) are examples of 3D silicates.

### Final Answer:
The examples of three-dimensional silicates are **zeolites, ultramarines, and feldspars**.